Pytest fixture scope

#pytest   #unittest   #python   #fixture   #scope  

---

Table of Content

Pytest fixture scope

A test fixture is a piece of software that sets up a system to satisfy certain preconditions of the process

In Pytest we use the fixture function as an input parameter of the test function.

• Function
• Module
• Class
• Session

pytest.ini

Set logging test capability before run test scope snippets

[pytest]
log_cli = True
log_cli_format = "%(asctime)s -- %(name)s %(lineno)d --  %(levelname)s %(message)s"
log_cli_level = DEBUG

Function scope

import pytest


@pytest.fixture(name="_init")
def setup() -> None:
    logging.info("-- run setup fixture before test --")

def test_1(_init: Callable) -> None:
    logging.info("run test 1")
    assert True

def test_2(_init: Callable) -> None:
    logging.info("run test 2")
    assert True

output

---

module scope

module scope

import pytest


@pytest.fixture(name="_init", scope="module")
def setup() -> None:
    logging.info("-- run setup fixture before test --")

def test_1(_init: Callable) -> None:
    logging.info("run test 1")
    assert True

def test_2(_init: Callable) -> None:
    logging.info("run test 2")
    assert True

output

---

Class scope

class scope

@pytest.fixture(name="_dummy", scope="class")
def dummy_data(request) -> None:
    request.cls.name = "my_name"
    request.cls.age = 50
    logging.info("Execute fixture")


@pytest.mark.usefixtures("_dummy")
class TestCalculatorClass:
    def test_1(self) -> None:
        logging.info(f"Test 1 name: {self.name}")
        assert True

    def test_2(self) -> None:
        logging.info(f"test 2 age:  {self.age}")
        assert True

output

---

Session scope

Fixtures with scope session will only be executed once per session. Every time we run pytest, it’s considered to be one session

session

import logging
from typing import Callable, Iterator
import pytest


@pytest.fixture(name="_init", scope="session")
def setup() -> None:
    logging.info("-- run setup fixture before all tests --")


def test_1(_init: Callable) -> None:
    logging.info("run test 1")
    assert True


def test_2(_init: Callable) -> None:
    logging.info("run test 2")
    assert True

output

---

Scope order

import pytest
import logging

@pytest.fixture(scope="session")
def session():
    logging.info("scope session")

@pytest.fixture(scope="package")
def package():
    logging.info("scope package")

@pytest.fixture(scope="module")
def module():
    logging.info("scope module")

@pytest.fixture(scope="class")
def class_():
    logging.info("scope class")

@pytest.fixture(scope="function")
def function():
    logging.info("scope function")

def test_order(module, class_, session, function, package):
    assert True

output

---

Reference

• Understand 5 Scopes of Pytest Fixtures